You've reached the Virginia Cooperative Extension Newsletter Archive.
These files cover more than ten years of newsletters posted on our old website
(through April/May 2009), and are provided for historical purposes only.
As such, they may contain out-of-date references and broken links.

The first three tables show results of several commercial insecticides that we have evaluated against alfalfa weevil in Virginia. In most cases, insecticides significantly reduced alfalfa weevil numbers below that of the untreated check. Those insecticides that consistently gave superior control of alfalfa weevil larvae for approximately 14 to 21 days after treatment (DAT) include: Baythroid 2E, Furadan 4F, Lorsban 4E, and Karate 1E (= Warrior T 1CS).

The last table lists performance ratings of commercial insecticides reported in alfalfa weevil efficacy trials from other alfalfa producing states, as well as Virginia, for the period from 1993 -1997. This information is annually published by the Entomological Society of America in Arthropod Management Tests. We rated insecticides as either excellent (E), good (G), fair (F), or poor (P) depending on how well they controlled alfalfa weevil compared to their respective controls for up to three weeks.

1998 Alfalfa Weevil Insecticide Efficacy Trial;Pulaski Co., Virginia

Alfalfa weevil larvae/10 stems

Treatment

Rate(lb AI/ac)

0 DAT(21 Apr)

4 DAT(25 Apr)

8 DAT(29 Apr)

13 DAT(4 May)

20 DAT(11 May)

24 DAT(15 May)

Baythroid 2E

0.025

26.6ab*

0.0b

0.6b

1.0b

0.0d

0.6b

Furadan 4F

0.5

16.6abc

0.6b

0.0b

1.6b

0.0d

1.0b

Karate 1E

0.025

16.6abc

3.6b

0.0b

0.6b

0.0d

0.0b

Lorsban 4E

0.5

14.6c

0.6b

0.6b

1.6b

0.3d

0.0b

Check (untreated)

--

26.6ab

33.0a

33.6a

33.0a

9.0a

4.6a

*Means within a column followed by the same letter are not significantly different; LSD (P > 0.05).